The fragile substance of my soul
by psquare
Summary: Set Season 6. The wall in Sam's mind is barely holding. Castiel has a solution, but this might end up harming the brothers even more than the problem itself... Traumatised!boys with a fair dose of h/c, hell-torture and general ambiguity. Fun!


**_A__/N:_** This was written for a prompt from **phreakycat **in the first-anniversary h/c comment-fic meme at **ohsam** over at LJ. Apparently, two months without writing fic has made me a tad rusty, so, yeah, it took a while to get this fic up and running.

And because I have received complaints that I do not give sufficient warnings, **PLEASE PAY ATTENTION TO THE FOLLOWING WARNINGS. **Particularly if you are a type who gets queasy easily (kinda makes watching _Supernatural_ tough, then), or if you are eating, or if you want to read/think about pleasant things.

**Warnings:** SPOILERS for Season 6 all the way till 6.13: _Unforgiven_. **Plenty of blood, gore, vomit, violence, references to graphic torture and much disturbing imagery**. Mild swearing, present-tense, metaphor-abuse.

**Disclaimer**: I don't own _Supernatural_ or any of its characters.

**_The fragile substance of my soul_**_**  
**_

When it first happens, neither of them think it's such a big deal. Sam gets headaches pretty often, has been laid up with the migraines-from-hell more times than he cares to count, and after a year (_two centuries_) of being not quite himself (_of being torn apart, over and over_), both of them figure that it's about time the exhaustion caught up with him. So, when Sam gets listless on the road, pinching the bridge of his nose like he wants to rip it out of his face? Dean hands him some painkillers, turns down the music until it's a low background drone, and keeps driving.

Over the next two days, the headache becomes a constant; everything they do is punctuated by Sam, in the background, scrunching up his forehead like he wants those lines permanently inscribed there, popping Aspirin like it's the only edible thing for miles around. Dean quickly puts an end to _that_; the last thing they need is Sam getting a freakin ulcer, or something.

But when Sam looks up at him with watery red eyes as he snatches the bottle away, pained and bewildered, Dean thinks they might have a problem.

* * *

When Sam wakes up, he's in a hospital.

The first thing he registers is that it's cold – he's shivering in his thin hospital-issue clothes, rubbing his forearms in a desperate attempt to generate warmth – and that it's _empty_. He weaves through corridor after corridor, room after room, but there's nobody; no other patients, no nurses, no doctors (_no Dean_).

He finally collapses into an uncomfortable plastic chair, head spinning, incipient nausea churning at the pit of his stomach. _Where – what – what in the hell –_

"Sam!"

He jerks his head up, heart beating a harsh tattoo against his ribcage. "Dean?" He gets up and half-runs, half-stumbles to where he thinks the voice is coming from. _Sam_, _Sam_, over and over again in a voice that just hinges on the cusp of a scream, and Sam's fear and desperation goes up one more notch with every empty room, every empty corridor.

Finally, he finds Dean in the room where he'd woken up.

Dean's sitting hunched at the table by his bed, his back to Sam. The room's impossibly cold now; Sam's breath is forming giant white clouds as he calls out to his brother. "Dean? Dean, what's going on?"

Dean turns. His face is covered in bruises; there's blood running from his nose, his ears, from under his hairline in great thick rivulets down his face, but he's smiling. The blood runs over his lips, stains his teeth, and Sam feels an insane urge to go and wash it out. "Hey, Sam," Dean says. "Glad you could make it."

Sam steps back, shaking. "Dean, Dean, what –"

"What?" Dean frowns and shrugs. "Is something wrong?"

(_your face this place the world_)

But he doesn't say anything; he only gapes at his brother, lips moving soundlessly.

Dean laughs. "Look, dude. There's nothing to worry about, alright?" He spreads his arms and large wounds tear their way through them, from elbow to wrist. Blood spurts out, so much of it, too much to be normal, mixing with the blood from his head that's dripping down his shoulders, his chest, his arms, to form a puddle on the floor and Dean's still smiling smiling _smiling_ –

"No. _No_." Sam turns, his panic a physical thing that's shoving him toward the door, but the door's locked (_of course it's locked_), and it won't budge, how much ever he throws his shoulder into it. Dean grabs his elbow in a warm, slick grip. "Wait, Sam, let me show you –"

Sam pushes away his brother (_not him not him_) and swirls around to try and find any other means of escape, but he slips on the bloody floor, falling on his side on the blood that's now coating _everything_, dripping from the ceiling, straining from the corners of the walls, little tracks forming crazy patterns across the peeling white paint. Sam can hear a dull roaring in the distance, picking up intensity with every moment, and it sounds like – it sounds like –

(_ten billion people who want you to suffer with them, sammy_)

"Sammy." Dean's standing over him, covered in thick, dripping red, holding out a hand. "Let me show you. I know you want to know."

Sam stares and stares and reaches up with his own hand (_i've seen all of this and more but i need to know_), but –

"_Sam_!"

The world shatters and dissolves, and Sam wakes up again.

Dean's tugging on his arm, eyes shining with naked fear. They're in the front of the Impala, and there's no blood apart from what's rushing through his ears; no white but the sunlight that's piercing his eyes with knife-points; no cold but the white rush of pain in his head that ebbs and flows with every beat of his heart.

He thinks he says, "Dean," and he really wants to say, _it hurts dean it hurts so much i don't know what's wrong with me_, but he knows Dean understands; Dean's always understood.

"I gotcha, Sammy, I gotcha," he hears Dean say, before the pain pulls him under.

* * *

Dean can't believe this is happening.

Sam had slipped into yet another restless sleep on yet another long, endless drive – _found us a hunt, _Dean told him, but he was thinking more along the lines of seeing-the-second-biggest-ball-of-twine-in-the-continental-US-and-maybe-the-Grand-Canyon kind of vacation – his face scrunched up in that perennial headache. They stopped at a couple of diners on the way, where Dean tried his best to convince Sam to eat something beyond a couple of listless spoonfuls of soup, but then Sam gave these pathetic, tired looks at him, eyes red and wet, and Dean couldn't really push the matter further (except decide that, vacation? _Hell_ yeah).

Then as Dean finally stopped at a random motel for a bit of shuteye, Sam wouldn't wake up. Dean shook him, shouted his name (_oh god he can't be remembering he can't not now not now not ever_), only for Sam to wake up, make this hideous groaning noise, and pass out _again_. Dean half-dragged, half-carried him inside their room, got him settled on the far bed, sat down on his own and commenced freaking-out.

Sam's breathing is ragged, agitated, and he's making small motions with his hands, like he's trying to push something away. Dean doesn't know what this – can't be another hell-seizure, can't be, not when he's been so damn _careful_ in trying to make sure Sam doesn't come across anything even vaguely triggering – but something's definitely _wrong_ with his brother, wrong enough that Dean knows he can't fix it on his own, and _goddamn_. Doesn't that kind of define his whole friggin life?

He's flipped open his phone and ready to hit speedial for Bobby's mobile when he sighs out a quiet _screw this_, flings the phone on the bed and closes his eyes. "Cas," he says, "if you're listening, I know you're busy with the war and everything, but, uh." He swallows. "I – we could kinda use your help right now. Something's wrong with Sammy, and –"

"Dean." The voice comes from a point right above his shoulder, and Dean twists around to see Castiel right behind him, face as impassive as ever. "What's wrong with Sam?" The angel walks around to Sam's side, already placing a finger against his pulse point, hand moving upward to check his temperature. It rests against Sam's forehead for a brief moment, and the lines there ease, Sam's restless movements finally stopping.

"Nothing like introductory banter with you, is there," Dean mutters. "I don't know, Cas. It started with headaches a few days ago, and now he's – well, he's like this, and I don't know if it's got to do with his whole soul-returning thing, or the wall in his mind, so –"

"So you want me to check." Castiel narrows his eyes. "You _are_ aware that the more you try to patch-up this problem, the more Sam will suffer."

Dean takes a deep breath. "Spare me the told-you-so speech, Cas, just, please. Check him."

"Very well." Castiel places his hand on Sam's head again.

"Uh, so, no plunging hands in chests anymore? Not that I'm complaining, y'know."

Castiel cocks his head. "Do you have reason to suspect that his soul is missing again?"

"Uh, no."

"Then that line of investigation will be redundant." The angel closes his eyes, brow furrowing in concentration. Dean isn't sure how long this will take – he knows Castiel has a tendency to get so lost in his work it's like talking to a frickin stone – and is just considering the merits of sitting with his thumbs up his ass, staring at Castiel like a preschooler, against actually going out for a bit and grabbing a bite to eat, when Castiel opens his eyes and takes his hand away. Sam sleeps on, completely oblivious.

"Well?"

"The wall, as you call it... is intact. However," Castiel raises grave eyes to meet his, "that won't be the case for long."

Dean frowns. "What do you mean?"

Castiel tells him.

* * *

Sam thinks he understands.

Dean's obviously not happy with things; he stumbles and growls through his explanation while Cas stands to the side, staring with familiarly eerie focus on a ceramic frog on Sam's nightstand. The wall in his head is under pressure, Dean tells him. There's just too much for it to hold back. Sam's hell is straining against it, and it's this pressure, it's this force, that's slowly killing Sam.

_Like a mental pressure cooker_, Sam thinks to himself with a rueful little smile, which, of course, doesn't help calm Dean.

"This isn't funny, Sam," Dean snaps. "Look at what this shit is doing to you, man, I can't believe we got such a crappy deal out of Death."

Sam shifts on the bed, clenches his teeth and rides out the starburst of pain in his head that the movement evokes. "Like we've ever been on the good side of a deal with a supernatural being."

Dean tilts his head. "Touché." He sighs and runs a hand through his hair. "That's not even the worst of it, though. Just wait 'til you hear the genius plan to fix this."

"Can't Cas, I mean," Sam shifts his gaze to the angel, suddenly uncomfortable about talking about Castiel like he's not there, "can't you fix this? I'm okay now – bit of a lingering headache, maybe, but –"

Castiel's eyes don't move. "I can't, Sam," he says. "If anything, what I'm doing is very temporary, and ultimately, ineffective. This is something you will have to deal with on your own." Now Castiel does look at him, and there's an ancient sadness in every line of that too-young face. "You're going to have to let the pressure out a little bit, every now and then, before it builds to an extent that can kill you."

"You mean, I –"

"It's not going to happen." Dean gets up, begins to pace. "I mean, you slipping into a hell-memory-seizure or whatever the hell that is? It's asking for trouble."

"But it does make sense," Sam says quietly. "It's like a safety valve, yeah?"

Dean raises his eyebrows. "Are we comparing your freaky head to machinery, now? Wait, actually that's kind of appropriate. _But_," he snaps his hands together in a gesture of finality, "Not happening. Sorry."

Sam's opened his mouth to argue, but Castiel gets there first. "Sam," he says. "Do you remember your wall?"

Dean gives a double-take, while Sam just frowns. "What?"

"Your wall, Sam. I suspect you saw it. You saw it disintegrating."

Sam's about to respond with a _I have no idea what you're on about_ when he gets it: that bloody hospital room, Dean bleeding out everywhere, asking him if he just _wants to know he'll show him everything he wants to know wants to know wants –_

"Dean's my wall?" Sam says with slow wonder. There's a quaintness to the idea that makes him want to laugh. Dean's torn between anger and disbelieving amusement if the sputtering noises coming from him are anything to go by, and Sam? Sam figures that it's kind of appropriate that the rickety recesses of his mind chose to construct Dean as the barrier that stands between him and his own personal Hell. It fits, he supposes.

He's barely wrapped his head around this when Castiel places his hand on his forehead again. "Let me show you something, Sam," he says, and moves the hand down to cover his eyes. When Sam can see again, he discovers that he's in another room, stark and grey except for a table in the centre. There's a half-eviscerated body on the table, the abdomen flayed open, coils of intestine hanging just over the edge. The man is still alive, still trying to scream, blood-shot eyes rolling crazily in his sockets.

Dean's there.

Dean's there, knife in hand, humming contentedly as he continues to cut through layers of gut with methodical precision. Hot blood splatters over his face as he ruptures an artery, and he giggles, he honest-to-god _giggles_, before licking the blood around his mouth and smacking his lips. He looks up at Sam, then, and his eyes – his eyes –

_his eyes are not even black_

Sam feels something give in the back of his mind with not even the barest hint of pressure, like a silk thread under twenty tons of reinforced steel.

He descends into hellfire.

* * *

Dean sits beside Sam until it's done, until his brother wakes up with a jerk and a muted gasp. Castiel's long-gone; he disappeared almost immediately after whatever the hell it was he did to Sam, knocking Sam headlong into another hell-seizure. Dean screamed at him – they hadn't _decided_ on anything yet, what the hell, how can Castiel just drop him like that – and asked him what he'd shown to Sam. Castiel merely replied, _I showed him the state I found you in when I came to rescue you from Hell_, and that? That shut Dean up.

Sam looks at him blearily before groaning and closing his eyes, rolling his head weakly against the pillow. Dean has a hand on his face then, rhythmically thumbing a lock of hair behind his ear – _I'm here, you're here, not going anywhere_ – but Sam still doesn't seem up to opening his eyes yet.

"Sammy." He tries to hold back the tremor in his voice. "Come on man, give me something here."

It takes a few moments, but Sam opens his eyes again, takes a deep, shuddering breath. "I'm okay, Dean," he says, even before Dean can open his mouth.

"Yeah," Dean says, "because what happened to you just now is the definition of 'okay'."

Sam pushes himself to a sitting position. "The headache's gone," he says, his voice strangely flat. "I guess it worked." He swings his legs off the bed, gets up and gives Dean a slightly watery smile. "Trust me, Dean, I'm fine."

Dean would be more inclined to believe him if Sam doesn't choose that moment to turn a shade of grey and rush into the bathroom to puke his guts out.

Still, Sam doesn't seem inclined to stay there, clams up like a friggin oyster when Dean tries to talk to him about what he'd seen – and yeah, now Dean's regretting his own stoic-in-sufferance act after he came back from Hell, if it set precedent for this – and insists that they leave the motel, hell, the _state_ (Florida, as it turns out – man, with all the mind-bending shit that happens to Sam over there? _So_ not normal) as soon as possible. Dean's definitely not against the whole leaving-bad-shit-behind plan, so they pack up, and get the hell out of dodge.

Weeks pass before it happens again.

There are moments when Dean fools himself into thinking the whole thing was just a one-off, hell, even a bad dream brought on by indigestion and too much whiskey. It's a comforting illusion to fall into, especially with Sam by his side, still healthy and sane (well, by Winchester standards, anyway), and still being _Sam_.

That's probably why it hits harder than the first time when it happens.

Sam's curled up in a ball on the bed, clutching his head, sweating and shaking. His cheeks are flushed with fever, and Dean gave up long ago to try and force him to eat anything save the occasional gulps of water, given Sam's tendency to upchuck everything that passed his lips, and then some. Sam moans and shakes and as Dean replaces the towel across his head with a cooler, wetter one, he knows what has to be done.

What the _hell_ kind of choice is it, though? To decide which method of torturing Sam is going to kill him slower?

(_A very Winchester kind of choice_, the melancholy part of his mind answers him, sounding startlingly a lot like Sam. He tells it to shut up, it's not helping.)

Dean leaves Sam's side, picks up his duffel and fishes out his largest knife. It's a beautiful thing, the polished blade gleaming in the yellow electric light. He kneels by the bed, face-to-face with Sam, his brother's glazed-over eyes barely focussing on his. He traces the blade lightly along Sam's cheekbones, applying just the right amount of pressure that Sam knows he's here, and what he's about to do.

(_didja miss me, Dean? because i did, you know. my favourite little student_)

"Dean?" Sam whispers, brow scrunching up.

Dean smiles. He shifts the blade downward, tip ghosting over the skin, down Sam's bare chest, stopping at his navel. "So how did he start, Sam? Did he gut you first? I don't know what it is, but man, they like to start off _real_ messy." He traced two lines across Sam's stomach, crossing each other. "You think, when they're pulling your intestines out, like they're friggin reeling back a fishing pole, nothing can hurt worse than this, _nothing_. And then," he moves his knife to Sam's crotch, and Sam's eyes widen. "You realise it can get worse. _Much _worse.

"Sometimes they look like Dad while they're doing it," Dean muses. His knife is back at Sam's chest moving along his collarbones, almost lovingly. "Sometimes they looked like you. So what about it, Sammy? Did I ever give you a surprise visit Down There?"

Sam shudders, closes his eyes. Dean reaches up and clutches his hair, pulling viciously. "No checking out on me, Sam – tell me!"

His brother stares at him, trembling, tears pooling in his eyes.

"What happened? Got your tongue pulled out?" Dean laughs harshly. "Yeah, that happens, right? Then they stuff it down your throat. Not fun." He leans forward, the knife-blade right in between their faces, point just centimetres away from plunging into the soft flesh of Sam's eyeball – "But that's all just foreplay, isn't it? They've done worse things to you. Worse things than ripping your heart right out your ribcage, worse than forcing you to eat your own intestines, worse than anything Alistair could've cooked up." Sam's so still now, still staring, staring. "_Didn't they, Sammy_?" Dean roars, knife point pressing into Sam's cheek just to draw the slightest amount of blood, and Sam's eyes roll back and he begins jerking on the bed.

Dean stares stupidly at Sam seizing for a long moment before he finally snaps out of it, throws the knife aside and tries to hold down Sam. But Sam's already stopped twitching; his eyes are closed, and he is so still that Dean has to concentrate hard to see the rise and fall of his chest.

Dean stumbles off the bed, shaking, feeling like he'd just been hollowed out with a butter knife. (_such a good student you remember so much don't you you liked it so damn much_) He pours out a glass of whiskey and drinks, the alcohol going down with a barely-felt burn, so he pours himself one more.

He's halfway through his fifth glass when Sam wakes up. He moves clumsily to his brother, tries to take him in his arms, but Sam flinches away from his touch and curls up on his side, sobbing raggedly into the bedsheets.

The third time it happens, it's only a week later. It's fire that does it this time, an unfortunate little rat that Dean catches and douses with gasoline and touches a lit match to. Sam goes down hard, seizing, but at least he's not screaming in pain like his head's about to burst, blood dripping from his nose and ears (_at least he's not dying in a way that Dean will recognise_).

When Sam wakes up, he doesn't move away from Dean. He presses his face into Dean's chest as Dean takes him in his arms, and cries.

* * *

Sam knows that this charade is wearing them both down.

He tries to hide his symptoms these days – as they come, regular as you like, every three to four weeks – just so that he doesn't have to see his brother wearing himself down to nothing, but when the pain hits... when it's like an atomic explosion on slow-mo inside his head, there isn't much he can do. Sometimes he catches the Dean of his dreams, Wall-Dean as Sam's come to call him, in the periphery of his vision just before the worst of the pain hits, but Wall-Dean is not very effective as a warning.

His little trips down memory lane are draining, but they're little more than a confused amalgam of fire and blood and agony, as he's buffeted between tortures too varied to be able to register properly. He wakes up every time with an inchoate feeling of hopelessness, shaking with sheer terror and seeking out his older brother for comfort like he's all of five years old again.

But, _Dean_ –

Dean scares him more than anything else.

It's eating away at him, to have to draw from his own experiences in Hell to try and trigger Sam into memories of his own. Sam learns more about the four months (_forty years_) that his brother spent in Hell (_for him_), about the things he did and the things that were done to him than Dean would've ever told him under normal circumstances, no matter the number of tearful roadside confessions.

There are times when he looks at Dean when Dean doesn't know, and he doesn't like the shuttered way Dean holds himself now, eyes fixed on some distant point, troubled, haunted. He hates that he's the reason Dean went to Hell in the first place, and that he continues to be the reason Dean keeps going back, over and over again.

(_round and round and round into your hell and back into mine_)

They're in another featureless motel room, and Sam's tired, so damn tired, but he's clicking listlessly through articles on his laptop, trying to find them a hunt. They don't hunt as much they used to these days, and Sam figures they (_Dean_) could do with the distraction. Dean's lounging on the bed, watching TV, already on his third beer of the evening.

The screen blurs in front of Sam, and he yawns. He closes the laptop, stretches, stifles another yawn. Maybe there's just no fighting it, he thinks. He flops back onto his bed with a sigh, and thinks he hears a faint _good night, Sammy_ just before he slips into oblivion.

He's back in the hospital room.

He sits up, looking around. There's no blood this time, just Wall-Dean leaning against the table, arms crossed over his chest.

"Didn't think we'd meet again," Sam says after a long silence, drawing his knees up to his chest.

Wall-Dean shrugs. "Just a matter of time, Sammy." He grins. "'S not like we had a great introduction last time, huh?"

Sam sighs. "What are you doing in here? I mean, in my mind? It's not like you're doing a bang-up job of keeping my memories of Hell at bay, or anything."

"Ooh." Wall-Dean hisses. "Harsh." He pauses, cocks his head. "Or it _would_ be, if you assume that that's what my job here really is. But it's not."

"It's not?"

"Nope." Another grin. "Oh, don't worry, your precious wall's still there – although, I gotta say, you were pretty stupid if you thought that that was all you needed to keep everything under control – but me? I'm here to guide you through your final step."

Sam snorts. "Right, now you're some kind of mental self-guidance book on the 101 Things You Need To Take Care Of Post-Hell?"

Wall-Dean opens his mouth like he's going to retort, considers it for a second, before breaking out in a smile again. "Y'know, that's exactly it. Nail on the head, Sammy." He pulls up the chair right by Sam's bed and settles down. "Think about it. What you guys are doing – recipe for disaster. It's not working."

"It's not like we have a choice –"

"Choice! See, that's it." Wall-Dean's hand comes down on the bed-railing, making Sam jump. "You're refusing to think out of the box. What's behind that wall... it's bad, really bad. But it's nothing you can't handle."

Sam laughs disbelievingly. "Yeah, tell _that_ to the people who keep reassuring me I'll end up a gibbering mess if that thing so much as even cracks a little bit!"

Wall-Dean shrugs. "They're wrong. Who're you going to believe, a bunch of demons and angels – by the way, how did the whole trusting-angels thing work out for ya last time? – or me? I've been in your mind since it first came into existence; trust me when I say I know you better than you know yourself."

Sam dips his face into his arms. "This is so surreal," he mutters.

"The thing is, Sam, I can help you. I can guide you behind the wall, because, what's going on right now? It's killing you _and_ Dean, and you know it. But you can fix this, Sam. You can come behind the wall with me, and you can discover who you _really_ are – instead of living a half-life with your memory full of holes, making you and your brother suffer for no reason at all."

Sam looks up, and there's Wall-Dean, almost Castiel-like in the way he's gotten his face into Sam's personal space now, eyes wide and green and earnest. "And if it changes me?"

Wall-Dean gives a howl of laughter, leaning back. "Of course it'll change you, Sam! But here's the thing: you decide what you become. You've drunk demon blood, you've hosted the devil, and you're still here. Those who doubt haven't considered who you _really_ are."

Even as Sam stares, Wall-Dean stretches out one hand, offering. "What do you say?"

(_you didn't need the feather to fly_)

- But it's _Dean. _He's going to have to face his past at some point anyway; he might as well do it on his own terms. Sam licks his lips. "Okay," he says. "Okay."

He takes his brother's hand.

_**Finis**_


End file.
